1. Field of the Invention
The present invention relates to systems and methods for electromagnetic waveguides, and in particular to systems and methods for switchable electromagnetic waveguides in spacecraft.
2. Description of the Related Art
In spacecraft applications, it is often advantageous to combine Traveling Wave Tube Amplifiers (TWTAs) to increase signal broadcast power, while retaining the ability to optionally use the TWTAs singly. Such a need often occurs in Ku Band applications where multiple power amplifiers may often be used. Similarly, it may be advantageous to temporarily divide the output of a single TWTA. Switchable waveguides can be used to perform these functions.
A hybrid waveguide junction, such as a magic tee junction, can be used to combine or divide power. Additionally, a cylindrical waveguide Variable Power combiner/Divider (VPD) can also be used to perform these functions. However, these conventional solutions are more difficult to implement, very expensive and require significant time to manufacture.
Furthermore, in the design of spacecraft, there are certain constant desirable objectives, which tend to vary only in emphasis for any particular application. These include reducing the mass and size of spacecraft components, reducing the time required to build components, improving the manufacturability, and of course, reducing component cost.
There is a need in the art for smaller, lighter, simpler and cheaper devices and methods for switching and combining electromagnetic signals. Particularly, there is a need in the art for a switchable waveguide which duplicates the functionality of a hybrid waveguide and two switch combination or a VPD.
The present invention satisfies these needs.
To address the requirements described above, the present invention discloses an apparatus and method for switching electromagnetic radiation conducted through waveguides that is lighter, simpler and cheaper than prior art devices.
A waveguide switch comprises a housing having a first, second and third housing port and a waveguide rotor, having a first and second rotary position. The waveguide rotor includes a junction waveguide, having a first, second and third junction port, for combining the first, second and third housing ports in the first rotary position and a bypass waveguide, having a first and second bypass port, for connecting the first and second housing ports in the second rotary position. The junction and bypass waveguides are alternately selectable by rotating the waveguide rotor to the first and second rotary positions.
A method of switching electromagnetic radiation conducted through waveguides comprises rotating a waveguide rotor including a junction waveguide having a first, second and third junction port and a bypass waveguide having a first and second bypass port, to a first rotary position in a housing including a first, second and third housing port, whereby the first, second and third junction ports connect the first, second and third housing ports and rotating the waveguide rotor to a second position a bypass waveguide, whereby the first and second bypass ports connect the first and second housing ports.
In one embodiment of the present invention, a switchable magic tee is employed in a single switch, which performs as two switches and a hybrid in combination. Combining these functions in a single unit significantly reduces the mass, and furthermore, eliminates the need for two switch driver cards. In addition, harness and interconnecting waveguide lengths are reduced. The overall result is a significant reduction in spacecraft mass.
Alternately, the switchable magic tee embodiment of the present invention can duplicate the functions of a cylindrical VPD. The VPD is a very complex device, comprising many elements that require significant expense and time to manufacture. The single switch device of the present invention is significantly less expensive and requires less time to manufacture than the VPD, and can be accomplished without need for special purpose manufacturing tools.
In one embodiment a switchable magic tee places the junction of a magic tee into the rotor of a switch along with two bypass waveguides. This is facilitated, at least in part, by an asymmetric transition step, added to each waveguide rotor port, either the bypass ports or the magic tee junction ports. This allows the rotor ports to be offset with respect to the housing ports.
Furthermore, the magic tee junction ports of the rotor have the mirror image configuration of the bypass ports and are also still electrically matched. This enables the waveguides in the rotor to exist in parallel planes, one above the other. A fourth magic tee junction port is directed out of plane with the rotor waveguides and routed out through a housing port with a choke joint and a large ring bearing.
The foregoing allows a lighter, simpler and cheaper device and method for switching and combining electromagnetic signals than presently known in the art and particularly, duplicates the functionality of a hybrid junction and two switches or a VPD.